﻿#region License
/*
Copyright (c) 2010, Dilyan Rusev
All rights reserved.

Redistribution and use in source and binary forms, with or without modification, 
are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this list
 of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright notice, this 
list of conditions and the following disclaimer in the documentation and/or other 
materials provided with the distribution.

* Neither the name of TU-Sofia nor the names of its contributors may be used to endorse or 
promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS 
OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#endregion

using System;
using System.Collections.Generic;
using System.ComponentModel;

namespace DbEngine
{
    /// <summary>
    /// Provides a cache for db type definitiona
    /// </summary>
    internal static class Mapping
    {
        /// <summary>
        /// Initializes the <see cref="Mapping"/> class.
        /// </summary>
        static Mapping()
        {
            Mapping.cache = new Dictionary<Type, object>();
        }       

        /// <summary>
        /// Get a cached db type definition
        /// </summary>
        /// <typeparam name="T">CLR persistent type</typeparam>
        /// <returns>Db type definition</returns>
        public static DbTypeDefinition<T> GetDefinition<T>()
        {
            object definition;
            if (!Mapping.cache.TryGetValue(typeof(T), out definition))
            {
                definition = new DbTypeDefinition<T>();
                Mapping.cache.Add(typeof(T), definition);
            }
            return (DbTypeDefinition<T>)definition;
        }

        /// <summary>
        /// Convert <paramref name="clrValue"/> properly to a string recognizable as a value by SQLite
        /// </summary>
        /// <param name="clrValue">Value to convert to string</param>
        /// <returns>Converted value.</returns>
        public static string GetSqlValue(object clrValue)
        {
            Type clrType = clrValue != null ? clrValue.GetType() : null;
            string sqlValue = string.Empty;

            if (clrValue == null)
            {
                sqlValue = string.Empty;
            }
            else if (typeof(string).IsAssignableFrom(clrType))
            {
                sqlValue = (string)clrValue;
            }
            else
            {
                var converter = TypeDescriptor.GetConverter(clrValue);
                if (converter != null && converter.CanConvertTo(typeof(string)))
                {
                    sqlValue = converter.ConvertToInvariantString(clrValue);
                }
                else
                {
                    sqlValue = clrValue.ToString();
                }
            }

            return sqlValue;
        }      

        private static Dictionary<Type, object> cache;
    }
}
